Generator Amperage

How to keep the Cessna 170 flying and airworthy.

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pojawis
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Generator Amperage

Post by pojawis »

Concerning our 14v generators, are they rated at 35 amps?
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Bruce Fenstermacher
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Post by Bruce Fenstermacher »

Yours could be. It could also be 12, 20 and 25 amps. Look at the tag on your generator which is the only way to be sure what you have.

Another clue but not by any means a definitive answer is the size of the fuse or breaker for the generator.
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pojawis
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Post by pojawis »

Thanks. The circuit breaker is 35A and the tag on the generator is 35A. Ordering Mr. H's service manual, part one, tomorrow. In the mean time, I thought I'd share the latest malady.

On the ground, the system appears to work normally. Ammeter registers at 1200 rpm. While in the air, I noticed that somewhere above 1800 rpm, the ammeter fluctuated regularly back-and-forth from + to -. Normal again on the ground. What might be the reason for this?
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tshort
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Post by tshort »

Are you running strobes?
My needle does some weird stuff when the strobes are firing...

Thomas
Thomas Short
1948 C170 N3949V
RV-8 wings in progress
Indianapolis (KUMP)
pojawis
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Post by pojawis »

Yes. Have one Whelen anti-colision strobe functioning. Was going to test that by turning on/off at altitude and see what the ammeter does. I just don't recall this happening before.
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blueldr
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Post by blueldr »

Your generator may need broshes.
BL
pojawis
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Post by pojawis »

Talked with the Zeftronics folks today and I'd like to reinforce Mr. Horn's comments on their hospitable service. They didn't know me from the Man in the Moon, yet they telephoned me, after hours, and spoke at length to address the problem I was experiencing with the generator.

Fortunately, it has been "fixed" with the first suggestion; to clean the reg to bus terminals as well as check & clean the battery leads and ground. After about 20 minutes of cleaning and reassembling, the ammeter reads normally. The fluctuations (in the ammeter needle) have ceased. The engine was ground run up to 2200 rpm with normal operation in the ammeter. We'll see if that changes in the air at higher rpms, but the initial test looks promising.

It was refreshing to find a company that practices a sincerely helpful philosophy and is not overly concerned with their bottom line. I'm sure they've found that when they "give away" their services, they establish a cadre of loyal customers.

Thanks for the help.
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